User Manual

ADCP-75-192 • Issue D • October 2005 • Section 1: Overview
Page 1-11
 2005, ADC Telecommunications, Inc.
3.7.5 Sonet Interface (SIF)
The Sonet Interface module provides the fiber interface between the Hub and RAN’s. This
interface includes:
1. Digitized RF Signal information
2. 10BaseT Ethernet for command and control between Hub and the RAN’s.
3.7.6 Hub Down Converter (HDC)
The HDC down converts the forward RF carrier to an intermediate frequency (IF) that can be
digitized. Each HDC can support up to four separate RF carriers. A second HDC may be
installed to support 5 - 8 RF channels.
3.7.7 Forward Simulcast Card (FSC)
The Forward Simulcast card converts the IF signals from the HDC to Digitized IF(DIF)
format. There are eight (8) separate analog-to-digital conversion circuits on one (1) FSC.
3.7.8 Reverse Simulcast Card (RSC)
The RSC sums the Digital IF (DIF) from up to eight (8) RAN’s into a single DIF signal that is
sent to the appropriate HUC for up conversion to RF.
3.7.9 Hub Up Converter (HUC)
The HUC accepts two (2) Digital IF (DIF) signals from a SIF or RSC. The two (2) DIF signals
are converted from digital-to-analog and provided as two (2) separate RF signals (primary and
diversity) to the BIM and BTS.
3.7.10 Base Station Interface Module (BIM)
The Base Station Interface Module provides the following BTS interface functionality:
1. Interface to a low power forward BTS RF path
2. Handles duplexed and non-duplexed signals
3. Gain adjust for optional reverse path configurations
The BIM is controlled via an I2C connection from its respective CPU.
3.7.11 Hub Reference Module (HRM)
The HRM generates the RF reference and fiber clocking for distribution within the Hub. In
addition, it contains a GPS that generates a 1 PPS (one pulse per second) for distribution to the
Digital Chassis modules for delay management.